What are the treatment strategies for nausea and vomiting in pregnancy?

Treatment Strategies for Nausea and Vomiting in Pregnancy

A stepwise approach starting with non-pharmacological interventions followed by vitamin B6 with doxylamine is the recommended first-line treatment for nausea and vomiting in pregnancy, with more intensive therapies reserved for moderate to severe cases. 1

Assessment of Severity

Before initiating treatment, assess severity using the Motherisk Pregnancy-Unique Quantification of Emesis (PUQE) score:

• Mild (≤6 points)
• Moderate (7-12 points)
• Severe (≥13 points)

The PUQE score evaluates:

• Duration of nausea (hours)
• Number of vomiting episodes
• Number of dry heaves

Treatment Algorithm

Step 1: Non-Pharmacological Approaches (All Patients)

• Dietary modifications:
  • Small, frequent, bland meals
  • BRAT diet (bananas, rice, applesauce, toast)
  • High-protein, low-fat meals
  • Avoid spicy, fatty, acidic, and fried foods 1
• Lifestyle adjustments:
  • Identify and avoid specific triggers (strong odors, activities)
  • Stay hydrated with small, frequent sips of fluid 1
  • Ginger 250 mg capsules four times daily 1
  • Consider acupressure at P6 point (wrist) 2

Step 2: First-Line Pharmacological Treatment (Mild-Moderate Symptoms)

• Vitamin B6 (pyridoxine) 10-25 mg every 8 hours, alone or with:
• Doxylamine 10-20 mg at bedtime or every 8 hours 1

This combination has a pregnancy safety rating of A and is recommended as first-line pharmacological treatment 3.

Step 3: Second-Line Pharmacological Treatment (Moderate Symptoms)

• Metoclopramide 5-10 mg orally every 6-8 hours (safe in pregnancy with no significant increase in risk of major congenital defects) 1
• H1-receptor antagonists such as promethazine or dimenhydrinate 1

Step 4: Third-Line Treatment (Severe Symptoms)

• Ondansetron 4-8 mg every 8 hours (use with caution in early first trimester due to small absolute risk increase for orofacial clefts and ventricular septal defects) 1

Step 5: Refractory Cases/Hyperemesis Gravidarum

• Hospitalization for:
  • Dehydration
  • Weight loss >5% of pre-pregnancy weight
  • Electrolyte imbalances 1
• Intravenous fluid and electrolyte replacement
• IV thiamine supplementation (100 mg daily for minimum 7 days, followed by 50 mg daily until adequate oral intake) 1
• Corticosteroids for refractory cases (avoid before 10 weeks gestation due to increased risk of oral clefts) 1

Important Clinical Considerations

1. Early intervention is critical to prevent progression to hyperemesis gravidarum, which affects 0.3-2% of pregnant women 1.

2. Timing of symptoms: Nausea and vomiting typically begins at 4-6 weeks gestation, peaks at 8-12 weeks, and usually subsides by week 20 1.

3. Medication safety concerns often lead to undertreatment. Reassure patients that recommended medications have established safety profiles in pregnancy 4.

4. Avoid these common pitfalls:

   • Delaying treatment due to unfounded concerns about medication safety
   • Using ondansetron as first-line therapy in early first trimester
   • Failing to recognize hyperemesis gravidarum requiring hospitalization
   • Overuse of stimulant laxatives 1

5. Medications to avoid or use with caution:

   • NK-1 antagonists like aprepitant (limited human data in pregnancy)
   • Second-generation antipsychotics like olanzapine (linked to increased risk for ventricular and septal defects) 1

6. Monitor for complications of antiemetic medications:

   • Extrapyramidal side effects with metoclopramide
   • Sedation with antihistamines
   • QT prolongation with ondansetron in patients with cardiac risk factors 1

By following this stepwise approach, most women with nausea and vomiting of pregnancy can achieve symptom control while minimizing risks to both mother and fetus.